After careful planning. Jammu Manufacturing Corporation has decided to switch to a just-In-time inventory system as a component of the lean thinking model. At the beginning of this switch. Jammu has 20 units of product in inventory. Jammu has 2.000 labour hours available in the first month of this switch. These hours could produce 500 units of product. Customer demand for this first month is 420 units. If just-in-time principles are correctly followed, how many units should Jammu plan to produce in the first month of the switch? (adapted from textbook)

A. 370

B. 400

C. 430

D. 470

E. None of the above.